Module 6

• Module Overview


  This module discusses spraying and dusting equipment
• Intended Learning Outcomes


  • Learn the primary functions of sprayer
  • Learn about terms related to spraying and dusting equipment
  • Solve problems related to seeding and planting
• Primary Functions of Sprayer

  • To break liquid droplets of effective size
  • To distribute the droplets uniformly over the surface or space to be protected
  • To regulate the amount of chemical solution in order to avoid excessive application that might prove harmful or wasteful
• Related Terms


  • Application Rate
  • Active Ingredient Rate
  • Formulation Rate
  • Spray Rate
  • Deposit Rate
  • Drift
  • Formulation
• Application Rate


  The amount of any material applied per unit treated
• Active Ingredient Rate


  The amount of active ingredient applied per unit treated expressed in terms of mass per relevant unit treated
• Formulation Rate


  The amount of chemical formulation applied per unit treated
• Spray Rate


  The amount of spray liquid applied per unit treated
• Deposit Rate


  The amount of any material deposited per unit area
• Drift


  The movement of chemicals outside the intended target area by air mass transport diffusion
• Formulation


  The form of a chemical that is supplied to the user, and which includes both the active and the inert ingredients
• Classifications of Sprayer


  • Hand Sprayer
  • Power Sprayer
• Compressed Air Sprayer


  • Simple in design and operation and are relative inexpensive to buy and maintain
  • Particularly useful for spot and small-area application
  • Tank capacity usually 7.5 to 15 liters and nozzle operating pressure up to 3.5 kg/cm2
• Knapsack Sprayer


  • They are carried at the back by means of shoulder straps
  • Simple in design and operation and relatively cheap to buy and maintain
  • Capacity is up to 22.5 liters and capable to operate at a pressure of 4.2 to 5.4 kg/cm2
  • They are useful for boom spraying when series of four nozzles or more are operating at the same time
• Hand Operated Sprayer Parts

  • Agitator
  • Drop tube
  • Rotor
• Power Sprayer


  • These are spraying apparatus that transport or operated with power source such as tractor, small engine, or electric motor
  • Usually used plunger or piston pumps
  • Usually operates at a pressure of under 40 kg/cm2
• Basic Parts of Power Sprayer

  • Agitator
  • Drop tube
  • Rotor
• Agitator


  A rotating device located inside the hopper of gravity flow applicators and broadcast spreaders that enhances delivery of granules to the adjustable orifice
• Drop tube


  A conduit either plastic, metal or rubber that directs granule flow of a granular applicator from the metering device to the target
• Rotor


  A metering device used in positive displacement granular applicators that regulates flow rate by displacing a fixed rate per revolution
• Types of Sprayer Nozzle

  • Cone-type nozzle
  • Fan type nozzle
  • Impact type nozzle
• Cone-type nozzle


  • Consists of tip ad a core or swirl plate
  • Usually operate between 40 – 60 psi
  • They are lever operated
• Fan type nozzle


  • The shape of the hole is responsible for the shape of the spray and the angled formed
• Impact type nozzle


  • Pressurized liquid passes through the nozzle orifice which is relatively large and strikes the angled face
• Spray Classification


  • Aerosol
  • Mist
  • Fine Spray
  • Medium Spray
  • Course spray
• Aerosol


  Distribution of droplets less than or equal to 50 um
• Mist


  Distribution of droplets greater than 50 um and less than or equal to 100 um
• Fine Spray


  Distribution of droplets greater than 100 um and less than or equal to 400 um
• Medium Spray


  Distribution of droplets greater than 400 um and less than or equal to 1200 um
• Course spray


  Distribution of droplets greater than 1200 um
• Methods of Application of Chemical

  • Banded Application
  • Basal Application
  • Broadcast Application
  • Directed Application
  • Foliar Application
  • Spot Treatment
• Banded Application


  Distribution of chemical in a parallel bands leaving the area between the bands free of chemicals
• Basal Application


  An application of chemical into the base of the plant
• Broadcast Application


  An application of chemical over an entire area of a field
• Directed Application


  An application of chemical to a specific area such as row bed or base of the plant
• Foliar Application


  An application of a chemical to the steam, fruit, leaves, or needles of the plant
• Spot Treatment


  An application of chemical to a small restricted area usually to control the spread of pest
• Calibrating Hand-Operated Sprayer


  1. Prepare the sprayer

  2. Determine the walking speed

  3. Determine the width of spray or swath

  4. Calculate the area sprayed

  5. Calculate the application rate

  6. Calculate the liquid herbicides or insecticides to mix in each sprayer per load
• Factors Affecting the Rate of Application

  • Pressure of the spray tank
  • Size of nozzle opening
  • Spray swath
  • Walking speed